The order includes 40 Boeing 737 MAX 8 and 25 of the smaller 737 MAX 7 aircraft, and follows an August 29th letter of intent from WestJet for the purchase. In a statement released with its letter of intent, the Canadian airline said the purchase was a central to its plan to modernize its fleet with more fuel efficient aircraft.

Gregg Saretsky, WestJet president and CEO, and Brad McMullen, vice president of North America Sales at Boeing, signed the firm purchase agreement at the WestJet campus in Calgary on Thursday.